what is the best rotation for execute phases? I understand the whole Reck/banner with CS, but after the first 4 executes under the CS effect, is it worth executing?

For fury, you typically will pool rage during execute phase and execute while the CS debuff is up. When the CS debuff is not up, pool rage, and use any RB procs until the next CS when you burn executes again.

Before you ask a question like this again in the future, I'd recommend going to world of logs, go to the rankings page on a fight you're trying to optimize your dps on, and analyze damage done for some of the top fury/arms ranked players.

After you identify a warrior you want to analyze (you probably want one that's in English), click on the name to go to the log itself.

Once you are there, Click on Dashboard -> Analyze -> Damage Done

For damage done, select "by spell" then choose the name of the warrior under the "Source" drop down menu and click on "Go"

Under the graph, you will see a drop down menu called "Filtering" which by default is set to "9 samples". Change that to "None".

Under that you will see a list of abilities. Deselect melee, and select the abilities of interest (e.g. Execute, Bloodthirst, Colossus smash, Raging Blow, etc"

You can now zoom in on the execute phase and see that person's exact rotation during the execute phase. Rinse and repeat for the top 10 or so logs to get a sense of what highly ranked players are actually doing.

You can also sim the rotation using a tool like simulation craft or do the rough math in a spreadsheet tool like google docs.